Drain trap



April 20, 1943. u. L. LAlsoN DRAIN TRAP Filed April 16, 1942 a/vo 4 Lama/v,

Patented Apr. 20, 1943 UNITED STATES PATENT OFFICE -Thi invention relates to drain traps for preventing the upward or reverse flow of water or suspended solids or gas from the sewer and is primarily intended for use in connection or association with the usual cast iron floor or basement or yard drain bell or bowl preferably having the usual provision for the usual water seal by the usual water retaining curve or elbow.

The provision of such a trap or traps in connection with such drains and of many difierent forms and types to automatically serve the function in view has long been well known at least from a theoretical standpoint and so far as disclosure by prior patents is concerned. However such automatic valves or traps have not gone into universal or even extensive use and this is probably due in large part to the factthat as heretofore known they involved excessive "original cost in the provision'of a special construction of drain bell or in the initial application of the trap to the bell or once installed were difi'iculttof access for repair, cleaning and general upkeep and maintenance or were of such construction as to be easily held unseated by an obstruction settling on the valve seat.

The present invention has been developed with the above considerations in mind and has for its primary objects to provide an automatic trap or valve unit for the above purpose which shall be of extreme simplicity and consist of an irreducible minimum of parts; to provide such a trap or valve unit which may be applied to any present known standard size and make of such type of floor or yard drain by simply forming suitable internal screw-threads in the upper end of the drain duct or pipe leading from the bottom of said drain bowl; to provide such a trap or valve unit which may be installed or removed by the most inexperienced novice or even a child; to provide in such a unit a ball valve which may have extensive wobbling movement with resultant action of moving to clear itself and its seat of any obstruction whereby the valve will properly function at all times to prevent the back flow of gas, water or'other material from the sewer or from below the trap or valve unit; and to provide such a unit in which the two normally immovable parts may be quickly separated for cleaning or replacement and in which said immovable parts in their normal operative relation will prevent theseparation of the ball valve while permitting the same a wide range of vertical, sidewise, angular-and turning movement or a wide range of universal movement.

In the accompanying drawing:

Figure 1 is a sectional view on the line I-I of Figure 2, looking in the direction of the arrows, the usual drain bell or bowl and usual associated parts being indicated in outline by broken lines; and

Figure a top plan view of the trap or valve unit in operative position in a drain bell or bowl broken away and indicated in broken lines.

Referring now in detail to the drawing, A designates the usual floor, yard or basement drain hell or bowl, with usually a perforated or slotted cover or top C set into the upper end of the bell or bowl and resting upon and supported by an annular face or shoulder, and with a drain pipe B leading ofi from the bottom of the bowl and formed into a water-seal containing elbow, all as long well known andas indicated in the drawing.

The inner wall of the upper portion of the drain pipe B at the point where it leads 01? from the bottom of the bowl or bell A and from the point where it intersects with the upper face of the bottom portion of said bowl or bell A will be internally screw-threaded as at 2 to receive the externally screw-threaded preferably thick metal disc I which is formed closely adjacent 2, marginal portion with a drain hole or perforation 3.

The upper face of the screw block or disc I will preferably be formed with a deep long narrow groove or slot 6 having walls preferably sharply perpendicular to the upper face of said disc or block I to receive the end of a screw-driver or a Wide thin bladed screwing-bar or tool or is otherwise equivalently formed to cooperate with an equivalent tool and serving to screw the disc or block I into or from the upper end of the drain pipe B according as the trap or valve unit is to be inserted into or removed from the upper end portion of said pipe B. Where such a groove or slot 6 is provided it preferably will be of such length that its respective ends approach the external face of the disc or block I substantially as closely as the outermost portion of the inner wall of the drain hole or perforation 3.

Preferably the lower portion of the wall of the hole or perforation 3 will be formed with internal screw-threads extending from and inter secting the lower face of the disc or block I and a tube or pipe 4 having its 'lower portion bent abruptly through approximately one hundred and eighty degrees to form a supplementary waterseal or to contain and hold a supplementary water-seal preferably has its extreme upper end portion externally screw-threaded and of such size as to screw into the internally screw-threaded lower portion of the hole or perforation 3 with a tight fit such that when a suitable coating of white lead, graphite, or equivalent material or other material functioning as a packing has been applied and the pipe 4 screwed into position it will make a gas-tight fit in the disc or block I.

The are of the bend or elbow of the pipe 4 will preferably be such that the longitudinal central point of the free end of the pipe 4, when diametrically opposite to the longitudinal center of the hole or perforation 3 will be disposed substantially at the same distance from the annular face of the disc or block I as is the said longitudi nal center of said hole or perforation 3.

The free end of the pipe 4 will be upwardly presented in the preferred form toward the op posed lower face of the disc or block I and will normally be closed by a ball 5 of such material, preferably some metal, and of such construction that it will not float in water or any liquid of similar nature. Such ball imaybe solid, or have a small central cavity, or of any construction so long as its weight is such that it will not float, but will sink through the liquid in the drain pipe B to seat itself in the upper end of tube or pipe 4 when there is not suflicient liquid within the bowl or bell A and the long leg of the pipe or tube 4 to raise the ball or valve 5 from its seat so as to permit the waste water or liquid to flow from the bowl or bell A through the pipe or tube 4 into the drain pipe B and finally from the latter into the sewer.

The diameter of the ball 5 will preferably be greatly in excess of the internal diameter of the upper or free end of the elbow portion of the tube or pipe 4 so that said ball will sit up on the free end of said tube or pipe 4 withroughlybetween two-thirds and three-fourths of its face exposed outside of said pipe or tube 4 and the diameter of said ball 5 exceeds substantially, or

preferably substantially, the distance between the lower. face of the block or disc I and the upper face of the free end, at all points thereof, of the pipe or tube 4 so that while the ball 5 has plenty of room for free play in all directions yet it is retained between said free end of the pipe 4 and the lower face of the disc I at all times and the disposition and relation of the parts is such that while the ball or valve 5 may be shoved upward to allow the escape of liquid into the drain pipe i B when such liquid has passed into the drain pipe B, except for such as remains in the elbow of pipe 4 as a supplementary liquid seal, the ball 5 must drop back by the action of gravity and seat itself in the free end of the tube or pipe 4.

The drawing hereof has been made from a full size sketch but the views of the present draw ing are not actual full size since it was necessary to make them on a reduced scale, roughly between two-thirds and three-fourths full size, in order to get both views on the single sheet. However, the relative sizes and proportions of the various elements were maintained.

While it is preferred that the upper end of the long leg of the pipe or tube 4 should be externally screw-threaded and screw into the internally screw-threaded lower wall portion of the hole or perforation 3 this construction and means of connection between these two parts is not essential and any suitable means of connecting said two parts together with a joint which may be conveniently made liquid and gas tight may be employed.

' While it is preferred that the disc or block I should be secured in position by screw-thread engagement this is not essential to my invention considered in its broader aspects, it being simply :essential when considered from this viewpoint that some simple efiicient means be provided for securing the block or disc I in operative position with a substantially gas and liquid tight joint between the same and the inner wall of the drain a liquid collecting bowl and a drain pipe leading from said bowl to discharge liquid by gravity from said bowl to a sewer, said trap comprising a disc externally screw-threaded to engage with internal screw-threads in the upper portion of said drain pipe to secure said unit in proper position in said fitting, said disc being formed with a large drain perforation extending through its upper and lower faces, and the lower portion of the wall of said perforation being internally screw-threaded, in combination with a discharge pipe with its lower portion bent to form an elbow to contain a liquid-seal and having its upper end portion externally screwthreaded and in liquid and gas tight screwthread engagement with the screw-threaded portion of the wall of said perforation, and a nonfloating ball valve normally closing the free end of said discharge pipe against the escape of backfiow liquid or gas through said discharge pipe, all portions of said elbow of said discharge pipe lying within the vertical plane .of said disc, and the diameter of said ball valve, being appreciably greater than the distance between the lower face of said disc and the upper face of the free end of said discharge pipe .to prevent the escape of said ball valve from operative relation to said discharge pipe.

2. A trap unit for use in a drain fitting having a drain pipe to discharge liquid by gravityfrom said fitting, said trap comprising a block to be mounted in the upper portion of said drain pipe in such manner as to form a liquid and gas tight joint between said block and said drain pipe, said block being formed with a large drain perfor ation extending vertically therethrough, and the lower portion of the wall of said perforation being internally screw-threaded, in combination with a discharge pipe with its lower portion bent to form an elbow to contain a'liquid-seal and having its upper end portion externally screwthreaded and in liquid and gas tight screwthread engagement with the screw-threaded portion of the wall of said perforation, and a nonfioating ball Valve normally closing the free end of said discharge pipe against the escape of .back- I flow liquid or gas through said discharge pipe, all portions of said elbow lying within the vertical plane of said block, and the diameter of said ball valve being greater than the distance between the lower face of said block and the upper face of the free end of said discharge pipe.

3. A trap unit for use in a drain fittingihaving a drain pipe to discharge liquid by gravity from said fitting, said trap comprising .a block to be mounted in the upper portion of said drain :pipe and formed with a large drain perforation extending vertically therethrough, the lower portion of the wall of said perforation being interthe free end of said discharge pipe against the escape of back-flow liquid through said discharge pipe, the diameter of said ball-valve being greater than the distance between said block and the free end of said discharge pipe.

UNO L. LARSON. 

